Detecting trace amounts of metal ions, such as fission products and radionuclides that result from nuclear reactions, is important for nuclear forensics. In addition, certain rare earth metal ions pose environmental and health risks, so accurate detection of such ions would be advantageous for environmental chemistry, biological chemistry, and medical diagnostics.
Two current approaches for sequestration of metal ions from samples are liquid-liquid extraction and ion-exchange chromatography. To maximize practicality, it is desirable to adapt these techniques to microfluidic environments, which would speed up the sequestration process and allow for application to portable nuclear detection devices. However, miniaturizing these techniques is challenging because small sample volumes require detection techniques to have low detection limits, fast response times, and high selectivity. Thus, there exists a need for increasingly sophisticated methods for the detection of trace amounts of certain metal ions in environmental samples that could be adaptable to portable devices.
The present invention addresses the problem of efficiently isolating and detecting trace concentrations of f-elements in environmental samples through the use of modified magnetic microspheres. The microspheres provide a platform for efficient and selective target ion extraction. Additionally, the microspheres' magnetic property allows for manipulation of their movement in microfluidic environments. The ability to control the movement of the microspheres is critical considering that molecular interactions in microfluidic environments are dominated by factors such as surface tension, energy dissipation, and fluidic resistance.